A conventional can body maker apparatus is disclosed in U.S. Pat. No. 3,696,659, issued to J. H. Maytag and an improvement to the ram assembly of the can body maker ram assembly is disclosed in U.S. Pat. No. 4,934,169, issued to C. M. Grimes, et al. Both of these patents are assigned to Adolph Coors Company. The aforedescribed patents are incorporated herein by reference as if fully set forth.
Can body makers produce elongated can bodies from shallow metal cups or can shells. The can shells have a wall thickness of approximately 0.009 to 0.012 inch, and the elongated can bodies have a wall thickness reduced to approximately 0.0045 inch. In a conventional can body maker apparatus, a ram is movably mounted for reciprocal, straight line motion at rates sufficient to form between about 180 and 220 can bodies per minute. The ram can be supported for straight line, or X-axis, motion by a mounting structure that incorporates fluid bearing technology. The stroke length, that is the distance traveled by the movable ram, is between about 18 to 26 inches.
In conjunction with the reciprocal motion of the ram, a redraw sleeve is supported in a redraw assembly. The redraw sleeve engages the shell prior to contact by the ram, applying a restraining force against the shell as the ram works the shell through a redraw die. The redraw process elongates the side walls of the can shell and decreases the side wall thickness and overall diameter of the can shell. The redraw operation is followed by two or three ironing stations that further elongate and thin the walls of the can shell to form a one piece can body. Finally, the body maker can be equipped with a doming station that further forms the enclosed bottom of the can body into a desired structural configuration and a stripper that performs the final operation on the can body. On the forward stroke of the ram, the redraw sleeve clamps the metal against a domer pressure ring to form the chime. As the ram makes contact with the domer die of the domer station, an air strip fills the ram and the can with pressurized air. When the ram begins its return cycle, the can is separated from the ram. It is the present practice to supply air to the air strip by a flexible hose directly attached to the ram and to switch the air on and off by a conventional valve.